Getting Started with GraphQL in Node.js

Modern APIs are evolving, and GraphQL is at the center of this shift. If you're building applications with Node.js and looking for a more flexible, powerful way to work with APIs, GraphQL is worth learning. In this beginner-friendly tutorial, we’ll explore what GraphQL is, how it compares to REST, and how to build your very first GraphQL server using Node.js.

What is GraphQL?

GraphQL is a query language for APIs and a runtime for executing those queries with your existing data. It was developed by Facebook and open-sourced in 2015. Unlike REST, which exposes multiple endpoints for different resources, GraphQL provides a single endpoint and allows clients to request exactly the data they need — no more, no less.

Here’s what makes GraphQL stand out:

• Single endpoint: All data is fetched via a unified endpoint.

• Precise querying: Clients define the structure of the response.

• Strongly typed schema: Everything is defined by a schema, offering great tooling and validation.

• No over-fetching or under-fetching: Just request the fields you need.

How is GraphQL Different from REST?

While REST APIs rely on multiple endpoints (e.g. /users, /posts), GraphQL uses a single endpoint and lets clients specify the shape of the data. Here’s a quick comparison:

Setting Up a GraphQL Server in Node.js

Let’s create a simple GraphQL API that returns a list of books. We’ll use:

• Node.js

• express - lightweight web framework

• graphql - core GraphQL library

• express-graphql - connects GraphQL with Express

Step 1: Initialize a New Project

mkdir graphql-node-tutorial
cd graphql-node-tutorial
npm init -y
npm install express express-graphql graphql

Step 2: Create the Entry File (index.js)

const express = require('express');
const { graphqlHTTP } = require('express-graphql');
const { buildSchema } = require('graphql');

// Sample data
const books = [
  { title: 'PatanGrid', author: 'Patan Sharukhan' },
  { title: 'GridPatan', author: 'Sharukhan Patan' }
];

// Define schema
const schema = buildSchema(`
  type Book {
    title: String
    author: String
  }

  type Query {
    books: [Book]
  }
`);

// Define resolver
const root = {
  books: () => books
};

// Create server
const app = express();
app.use('/graphql', graphqlHTTP({
  schema: schema,
  rootValue: root,
  graphiql: true, // Enables the browser tool
}));

app.listen(4000, () => {
  console.log('Server running at http://localhost:4000/graphql');
});

Step 3: Run the Server

node index.js

Open your browser and go to http://localhost:4000/graphql. You’ll see GraphiQL, an in-browser IDE for running queries.

Step 4: Try Your First Query

{
  books {
    title
    author
  }
}

The response should look like this:

{
  "data": {
    "books": [
      { "title": "PatanGrid", "author": "Patan Sharukhan" },
      { "title": "GridPatan", "author": "Sharukhan Patan" }
    ]
  }
}

Understanding Schema, Types, Queries, and Resolvers

Here’s what each part of the code does:

• Schema: Defines what data is available and how it's structured. In this case, we defined a Book type and a books query.

• Query: Represents the entry point for reading data. Clients use it to ask for specific fields.

• Resolver: Functions that tell GraphQL how to fetch the data for a type or field.

What’s Next?

Now that you’ve built a basic GraphQL server, you can start exploring more advanced topics like:

• Creating and updating data with mutations

• Using variables in your queries

• Connecting to a real database like MongoDB or PostgreSQL

• Adding authentication with JWT

• Pagination and filtering

Final Thoughts

GraphQL may seem intimidating at first, but once you get the hang of its core concepts — schema, types, queries, and resolvers — it becomes a powerful tool in your web development toolkit. With just a few lines of code, you've created a flexible and customizable API that's easy to test and scale.

In future tutorials, we’ll build on this foundation by adding real databases, authentication, and even fullstack integrations.